1. Field of the Invention
This invention relates to a vehicle having a hybrid power source operationally combining an internal combustion engine, such as a gasoline engine, diesel engine or gas-turbine engine, with an electric motor operating off current stored in a battery mounted in the vehicle and, more particularly, to an assembly including the internal combustion engine, a generator and the electric motor in a hybrid vehicle.
2. Description of the Related Art
The present invention can be applied both to a series type assembly and a parallel type assembly. Three types of hybrid arrangement are known. The first type is the series type assembly in which the hybrid vehicle moves under power of the electric motor operating on current generated by the generator driven by the internal combustion engine which is constantly running. The second type is the parallel type assembly in which both the internal combustion engine and the electric motor are arranged to relate to the drive wheels, but are selectively used. The third type is the series-parallel type assembly combining the series type and parallel type assemblies.
The conventional hybrid vehicle of the series type assembly has the internal combustion engine and the generator integrally combined and the electric motor or an electric motor and transmission unit separated therefrom. A motor vehicle typically mounts the electric motor and the transmission at its front portion, the internal combustion engine and the generator at its rear and the battery intermediate the front and rear.
However, in a passenger car, the internal combustion engine (with the generator), provided at the front of the vehicle, is cooled by ram air. Accordingly, the battery should be located either at the intermediate or rear portion of the vehicle. In consideration of providing sufficient interior space for passengers and a practical traveling distance on one battery charge, several batteries are typically arranged at the rear portion of the vehicle.
It has therefore been preferable to install the electric motor and the transmission unit at the front of the vehicle in a total plan for weight balance and interior space for passengers.
A certain clearance between the internal combustion engine and generator unit and the electric motor and transmission unit should be provided because the two units should be mounted in the vehicle separately to appropriately relate to different drive components and systems causing vibration, which separation requires a large space for the internal combustion engine, generator, electric motor and transmission unit in the vehicle. In the series type hybrid vehicle, such a disadvantage is conspicuous due to a relatively large generator, so that an arrangement aligning the internal combustion engine, generator, electric motor and transmission all together in an engine compartment at the front of the vehicle is impossible.
Even if such an arrangement could be fit into the engine compartment, somehow or other, the steering angle required for the front wheels to turn requires a large clearance circle and further requires separate cases for the internal combustion engine, generator, electric motor and transmission unit, which results in an increase in the number of parts, in weight and in the cost for manufacturing.
Giving precedence to the internal combustion engine and 35 the generator, the electric motor and the transmission unit are difficult to locate at the central portion of the vehicle, whereby the differential gear unit receiving driving power from the electric motor also tends to be located off-center of the vehicle, so that shafts laterally and oppositely extending from the differential gear unit have different lengths which causes a torque on the steering.